This question is part of the best-puzzle award series

What are your nominations for the best puzzles, here on Puzzling.SE, of the first quarter (January/February/March) 2024?

Suggested guidelines for nomination:

  • Nominate each individual puzzle in a separate answer, so they can be upvoted/downvoted separately.

  • No more than 3 nominations per person.

  • Don't nominate your own puzzles.

  • Before you nominate a puzzle, check to see if someone else has already nominated it. If they have, then add to that nomination as a comment (or edit it) instead of nominating the same puzzle again.

  • In your nomination, explain what it is that (in your opinion) makes the nominated puzzle such a good one.

Some lists to help jog your memory (your nomination doesn't have to be from these lists):

Algorithmically selected "best of":

Best by votes/views:

Meta-meta issues:

Q: Is this kind of thing allowed on SE?
A: Yes, Photography SE and Sci-Fi & Fantasy SE do something very similar.

Q: What's the point?
A1: To highlight and encourage good practice in a way that goes beyond upvotes.
A2: To work towards building a 'hall of fame' of some of the best puzzles on the site (perhaps to reside on a future puzzling.SE blog) - think of it as our 'greatest hits album'.
A3: To prompt members to put forward their own reflections on what makes a high-quality puzzle.


1 Answer 1


Invalid Jigsaw Sudoku Layout by JCO

I remember coming across this seemingly simple 'explain why...' puzzle (which asks the solver to justify why a particular blank jigsaw sudoku layout has no solutions) shortly after it was posted and thinking, "Well, this should be easy..." but then whilst trying to get my teeth into it suddenly finding it a lot harder than expected!

When @codewarrior0's excellent answer appeared, it felt all of a sudden like a fog had lifted. What had been a difficult problem to break into was now completely clear, with a thorough explanation, everything made sense, and this peculiar quirk of sudoku construction was laid bare for a reader to understand in its entirety.

The puzzle is not completely straightforward, the logic involved in understanding the puzzle is interesting, and the accepted answer is well explained with helpful diagrams throughout. This is an excellent post all round.


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